Enhanced pyroelectric figure of merits in Sr and Zr co-doped porous BaTiO₃ ceramics

Porous Ba_0.85Sr_0.15Zr_0.1Ti_0.9O₃ (BSZT + X wt% Poly-vinyl alcohol (PVA)) with X = 0, 5, 10, 15 ceramics were prepared by the conventional solid-state reaction method. Structural, dielectric, ferroelectric, and pyroelectric properties were systematically investigated with the increase in pore-forming agent PVA. X-ray diffraction (XRD) pattern shows co-existence of tetragonal and orthorhombic symmetries with space group P4mm and Amm2, respectively. Microstructure depicts the pore density in the ceramic samples increases with increase in PVA content. The temperature-dependent dielectric analysis illustrates that there is no change in Curie temperature (T_c ~ 327K) with the increase in PVA. Dielectric constant value decreases and dielectric loss increases with increase in PVA. The pyroelectric coefficient increases with the applied field and decreases with an increase in PVA. We observed strongly enhanced pyroelectric figure of merits (FOMs) with an increase in porosity content. At room temperature, porous BSZT ceramic sample (BSZT + 15 wt% PVA) exhibits a 29.17% increase in pyroelectric energy harvesting figure of merit F_e, 101.73% increase in energy harvesting figure of merit F_e^*, 81.93% increase in voltage responsivity F_v, 10.95% increase in current responsivity F_i, 24.97% increase in detectivity-based FOM compared to dense ceramic sample. The enhancement in these FOMs is useful in the development of pyroelectric devices.